1. Field of the Invention
This invention relates to suction catheters and suction control valves therefor. More particularly, it relates to on/off valves for suction catheters that are normally closed, but which may be opened for application of vacuum by mere pinching of a valve member.
2. Description of the Prior Art
Suction catheters are extensively used during surgical operations and in post-operative care for aspiration of mucus, blood and other fluids from nose, mouth, pharynx, trachea, bronchi, stomach or other cavities of the patient's body (see U.S. Pat. Nos. 3,848,604; 3,945,385 and 3,965,901).
Since the control of suction, either in extent of time or degree of vacuum may be required during use of suction catheters, it is conventional to provide such catheters, either as an integral unit or as an optional attachment, with suction control valves (see U.S. Pat. Nos. 3,375,828; 3,595,234 and 3,610,242).
Although internal valves for tubes that are of the normally closed type are known (see U.S. Pat. No. 274,447), it has been considered advisable in the past, for ease and accuracy of control, to use suction control valves of the normally open type with suction catheters. However, the known present open-port control valve suction catheters and Yankauer suction devices involve some disadvantages. Obviously, an open port wastes vacuum potential continuously. Also, the open port exposes the user to fluids that may spatter through the open port and present a source of possible cross infection. Depending on the level of vacuum used, the open port can create annoying hissing or sputtering noises. Additionally, since an open port type control may allow residual vacuum pressure at a catheter tip even when the port is "full open", there can be a tendency to evacuate air from a body cavity, e.g., the lungs, with the control port full open. Some users kink the sunction tube before introduction to guard against this problem.
Notwithstanding the numerous improvements that have been made in the past in the art of medico-surgical tube devices, including suction catheters and their control valves, there is need for further improvements to eliminate problems of use and design associated with such devices. Of course, if such improvements are to be effective, they should not introduce other problems or disadvantages that would negate their adoption and use by the trade.